A senior Wanganui district councillor said his council could not rule out legal action in the wake of the problems in the city's wastewater treatment plant.
The city, and some rural areas beyond the city limits, have been overwhelmed by a stench coming from the ponds since last weekend, believed to have been caused by a massive dumping of industrial waste into the system.
The council had been struggling to sort out problems at the plant and believed it was making headway before the weekend when an extra 56 tonnes of waste a day was pushed into the system in a few days. The normal daily input from wet industries is 10 tonnes a day.
Problems at the treatment ponds worsened this year and in the last month the council installed a bio-augmentation programme to speed up treatment which had literally become bogged down.
Councillor Ray Stevens, Wanganui District Council infrastructure and property committee chairman, said it was disappointing that just as the council was getting on top of the problem, progress was destroyed with a huge dumping of solid waste into the system: "We were making inroads with our bio-augmentation programme and sludge levels were dropping.
Then came the industry dumping a huge amount into the system."
That volume could only have come from one of the wet industries and he was unhappy the industry involved had not forewarned the council. That was being investigated and he would not rule legal action.
"The point is, the wet industries are obliged to tell us when this sort of thing is going to happen. Those industries supply 75 per cent of all the waste going into our treatment system and that's why they pay the greatest amount in levies.
"But when something like this happens, it has a detrimental affect and penalises everyone across the city," Mr Stevens said.
The industries were key partners in terms of the plant's effective operation and it was imperative they talked to the council.
"If they'd told us first, then we could have looked at some way of properly controlling this influx, perhaps by retaining some of it so not everything went into the system all at once."
Meanwhile, one Wanganui airport industry user said his company had been on at the council for two years to get the problem fixed, but nothing had happened. Ravensdown Aerowork operations manager Rick Harding said the company had considered legal action and had spoken to its lawyer, "but we haven't pulled that one out yet".
Mr Harding said the smell had been bad around the airport area for years but last Saturday was the worst: "If you'd been out here on Saturday you would have vomited, that's how bad the stench was."
He said now the smell had drifted over other parts of the city and the complaints had got stronger, the council was reacting.
The company had Chinese guests in the city last weekend to look at aircraft.
"They told us they could smell it even before they landed. It's become an embarrassment."
Mr Stevens said when the plant's problems worsened this year, the council met airport users and industries. "We explained to them what had happened and what we were doing to alleviate things, and we'll be updating them again within the coming days."